Passions: Derek LaFavor, Selling Source

Even when he's relaxing, Derek LaFavor doesn't slow down. When the 54-year-old isn't busy running Selling Source, the $130 million Las Vegas company he founded, in 1997, to process online loan applications for financial firms, LaFavor can often be found speeding along open desert roads. LaFavor has long harbored a love of fast cars, and five years ago, when his company reached more than $5 million in annual profit, he decided it was time to indulge his teenage fantasies. He started with a Ferrari 360 Spider and has amassed a collection of 14 sports cars, many of them American muscle cars from the 1960s and 1970s. "On Saturday mornings," he says, "the big question is, What do I feel like driving today?"

First love: A 1970 Plymouth Barracuda. LaFavor first caught a glimpse of the vehicle in a showroom when he was 16. "I was passionately in love with it," he says. "I always kept thinking about that 'Cuda." In 2004, he purchased a 1973 Barracuda for $8,500. He then spent more than $200,000 for a new transmission, a 1,000-horsepower engine, new wheels, and a full restoration.

Cost to fix them up: From $35,000 for a 1965 Shelby Cobra to more than $600,000 for a custom-modified 1967 Chevrolet Chevelle with a 1,200-horsepower twin-turbo engine

Muscle-car inflation: In 1967, LaFavor's Chevelle went for about $3,000.

Rarest muscle car on the market: The 1967 Dodge Coronet convertible with a 426 Hemi engine, according to Musclecarclub.com, a community for muscle-car enthusiasts. Only two of these cars are still around.

Most valuable muscle car on the market:The 1970 Plymouth Superbird 426 Hemi, valued at about $171,225 in unmodified condition

Scouting for cars: LaFavor pays five truckers to keep an eye out for old cars in farmers' fields and car lots as they drive across the country. He also works with VIP Custom Cars, a Missouri company that specializes in high-end vehicles. The company searches junkyards for cars he wants and soups them up for him.

Wish list: LaFavor is on the hunt for a 1955 Chevy Bel Air two-door and a 1970 Plymouth Roadrunner.

Speeding tickets: A few, says LaFavor. "They're a small price to pay for the pleasure of driving the cars the way they are meant to be driven."

Fastest speed he has ever hit: 130 miles per hour through the desert in his Ferrari 599 GTB